Incandescent electric lamp



(No Model.) I W. E. IIIQKlEiRSON.

INGA'NDESGENT ELBQTRIO L AMP.-

No. 503,671. Patented Aug. 22, 18 9 3.

WWI- 155555. I I' P W /vm UNITED STATES PATENT OFFICE.

"WILLIAM EMERY NICKERSON, OF CAMBRIDGE, MASSACHUSETTS.

INCANDESCENT ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 503,671, dated August22, 1893.

Application filed July 1'7, 1893. Serial No.480fl31. (No model.)

To all whom, it may concern:

I Be itknown that 1, WILLIAM EMERY NICK- ERSON, of Cambridge, in thecounty of MiddleseX and State of Massachusetts, have invented a new anduseful Improvement in Incandescent Electric Lamps, of which thefollowing, taken in connection with the accompanying drawing, is aspecification.

My invention relates to that class of incandescent electric lamps, inwhich the neck of the lamp globe is closed air-tight by a fusiblecement. It is illustrated in the accompanying drawing, which showspartly in Vertical section and partly in side elevation, a lampembodying my device.

In the drawing, A represents the globe of an incandescent electric lamp,the neck of which is provided with the shoulder a, upon which rests adisk of mica or other suitable substances D. The diskD servesprincipally, to support the plug of fusible cement E.

B is the filament, and O C the leading-in wires to which the filament isattached at b I).

G is a brass cap or base, surmounting the neck of the lamp, to which itis secured by plaster in the usual manner. The leadingin wires areattached to the cap by soldering, at c c.

F, is a layer of fusible cement of a diiferent composition from E, andwill be described hereinafter.

In a lamp of the class described in this specification, it is necessaryto use a cement whose fusion point is so high that it will not melt oreliminate gas or vapor, when the lamp is in operation. A cement of thisdegree of hardness and infusibility, is liable when exposed to a verylow temperature, such as may occur during the winter in cold countries,and sometimes from other causes, to lose its adhesiveness, and becomeseparated from the interior wall of the lamp neck, thereby allowing thelamp to leak. This defect I remedy, by using two layers of cement ofdifferent composition and degrees of fusibility and elasticity. Theharder and more infusible of these layersI placenext the supporting diskD. This layer is able to resist without melting or elimination of gas,the heat received from the incandescent filament. It may be composed ofrosin combined chemically with lime, and made somewhat flexible by theaddition of a certain quantity of a suit-able oil, and a.

granular substance, substantially as described in my PatentNo.500,075,granted June20,1893, for an incandescent electric lamp. Theother layer, shown in the drawing at F, may be composed of a similarcompound of rosin and lime, but contains a much larger proportion ofoil, whereby much greater flexibilityis obtained, so that itsadhesiveness is not destroyed by low temperatures, and no separationfrom the surrounding glass will take place. This effectually preventsthe leakage of air into the lamp, in case the layer of harder cement E,should slightly separate from the glass. Should such a separation takeplace on account of exposure to intense cold, the surface of the cementE and that of the glass will again unite, when subjected to the heatoccasioned by burning the lamp. The soft cement F is prevented fromcausing vapor in the lamp, by the hard layer E which underlies andprotects it.

The gist of my invention consists in the use of a layer of comparativelyhard and infusible cement next to the disk or vacuum wall of anincandescent lamp, and alay'er of comparatively soft and fusible cementoverlying it, for the purpose of preventing the leakage of air into thelamp, when intense cold, or other cause may have made the hard cement tolose its adhesiveness and separate from the surrounding glass.

While my invention applies especially to lamps which are to encounterintense cold, it is also useful under ordinary circumstances, since itenables a much harder and more infusible cement to be used, where thereis most danger of fusion and elimination of gas or vapor, therebyproducing a superior lamp.

I claim 1. In an incandescent electric lamp, afusible cement plug forclosing the neck of the lamp globe air-tight, said plug consisting oftwo layers, one comparatively hard and infusible, located nearer thefilament, and one comparatively soft and fusible, located upon andoutside the hard layer, substantially as and for the purpose set forth;v

2. In an incandescent electric lamp, the combination. of the glass globeA having a neck adapted to be closed by a plug of fusible name to thisspecification, in the presence of cement, the filament B, the leading-inwires two subscribing witnesses, on this 14th clay of C O and thecement-supporting disk D; with July, A. D. 1893.

WILLIAM EMERY NICKERSON. Witnesses:

FRANK G. PARKER,

FRANK G. HATTIE.

the layer of fusible cement E, and the softer 5 and more flexible layerof cement F, substantially as and for the purpose set forth.

In testimony whereof I have signed my

